The present invention concerns an automatic metering and filling machine, in particular for volumes of animal semen packaged in any kind of packaging member (by way of non-limiting example: cannulas, straws, catheters, tubes, flasks, etc) regardless of their diameter and of the material from which they are made. This device is more particularly, although not exclusively, suitable for insemination of poultry, such as turkeys, for example.
The equipment traditionally employed for artificial insemination of poultry, for example, conforms to various criteria allowing for the anatomical, physiological and economic peculiarities of these species. Four of these criteria are crucial in the case of industrial applications. These absolutely essential criteria are as follows:
1--dispensing, with the greatest possible accuracy, small volumes of pure or diluted sperm, for example; PA1 2--supporting very high rates of artificial insemination (several hundred inseminations per hour, by way of non-limiting example, between 500 and 800 inseminations per hour, in turkeys, depending on the number of inseminators); PA1 3--reducing or even eliminating the risk of horizontal (i.e. female to female) transmission of contaminating agents (for example Mycoplasms or Salmonella); PA1 4--easy and fast disinfection.
The construction of automatic metering and filling machines commercially available at this time does not satisfy all these requirements simultaneously. Although this equipment in all cases satisfies the last two of the specifications mentioned above, this is not so in respect of the first two. The equipment is designed on the principle of distribution using a syringe or an air suction system. The use of a syringe generally limits the speed with which doses can be dispensed and the use of an air suction system does not allow accurate metering of the liquid substance to be introduced into the interior of a cannula, for example. Consequently, and regardless of their qualities, this equipment is either very accurate and rather slow or fairly fast and somewhat inaccurate. What is more, most of this equipment is generally relatively costly and must in some cases be associated with a compressor, which does not facilitate the work of inseminators moving amongst animals or in poultry batteries, for example.
A machine for filling artificial insemination straws for poultry, for example, is described by the applicants of the present patent in Pat. Nos. 2,500,296 and 2,513,110. The invention has many advantages over the above machine, which is commercially available and in use at this time.
The existing machine utilizes a piston pump, unlike the invention, which uses a peristaltic cassette (as described, for example, in European patent application No. 81104214.2 (U.S. Pat. No. 4,702,679) filed by MALBEC) under the control of a digital controller. Accordingly, the invention removes all of the drawbacks mentioned in connection with the existing equipment.
The existing machine uses a device for clamping a tube by means of three separate members in metering and filling cannulas or any other packaging members with a liquid of any kind. The advantages of the invention include a compact system based on a peristaltic cassette containing a preferably flexible tube and rollers. (See U.S. Pat. No. 4,702,679 mentioned above. The pressure applied to the tube by said rollers delivers a dose. This principle is therefore substituted for the radial clamping members of the machine currently used.
Moreover, the central member of the existing machine having a fixed dimension, the dose is adjusted by limiting the travel of the central member, which sometimes leads to some inaccuracy in respect of the volume of the dose delivered. The adjustment is effected by limiting the travel of the central member by means of a screw and a key, which wastes a certain amount of the operator's time. In the new machine, on the other hand, the subject matter of the present patent, the adjustment is carried out by pressing on two buttons, preferably pushbuttons, either in a pulsed mode (fraction of a dose, for example) or in a continuous mode (passing a dose of 40 microliters to 50 microliters, for example). The dose is defined by a number of turns or of fractions of turns of the peristaltic cassette. Said number of turns or fractions of turns of the peristaltic cassette being controlled by a position control loop in turn controlled by a microprocessor, the dose delivered is therefore more accurate.
Turning to the function of priming the peristaltic cassette, when using the existing machine it is possible to observe the loss of some of the semen intended to be packaged in the interior of a cannula, for example, and contained within the feed tube. This is due to the configuration of the filler needle, which plugs in rather than clipping on, like that of the invention. It therefore does not benefit from a mounting device as practical and as perfected as that of the invention. Removing the needle requires the operator to clamp the feed tube, causing some loss of the fluid to be packaged and unpriming of the peristaltic cassette. Moreover, said tube must be manually inserted by the operator between the three obturator members of the cassette mentioned above, which frequently stretches the tube and consequently varies the volume of the dose delivered.